Flexible electronics are presently of significant interest and the subject of active research and development. To date, a variety of processes for fabricating flexible, thin integrated circuits have been demonstrated or suggested. One example is silicon-on-insulator (SOI) wafer-based processes, which typically rely on complementary metal-oxide-semiconductor (CMOS) technology. While CMOS-on-SOI approaches allow the use of well-developed and widely available foundry processes, custom integrated circuits (ICs) on SOI substrates must be produced for all functional components of the circuit. These IC die fabricated in the thin Si layer of the SOI wafer are then separated from the rest of the substrate and embedded into the flexible substrate. Another example is transfer printing, which involves transferring small “chiplets” from a source wafer to a flexible substrate. However, transfer printing requires custom components as well. Moreover, for complex, large-area circuits, transfer printing does not leverage traditional circuit design due to segmentation of the process into different chips, consequently reducing performance due to lag time. Another example is direct fabrication, which involves depositing amorphous silicon (Si) or poly-Si directly onto flexible substrates and fabricating transistors and other electronic devices on these flexible substrates. Thus far, however, direct fabrication has suffered from significantly reduced performance in comparison to state-of-the-art (CMOS) technology.
In view of the foregoing, there is an ongoing need for new or at least improved flexible and thin electronics and methods for their fabrication.